Mechanical linkage



April 1953 D. s. CHISHOLM 3,380,309

MECHANICAL LINKAGE Filed March 21,. 1966 2 Sheets-Sheet l INVENTOR.0009/06 6: C/I/S/w/m April 30, 1968 D. s. CHISHOLM 3,380,309

MECHANICAL LINKAGE Filed March 21, 1966 2 Sheets-Sheet :4

I N VE N TOR Daug/as 6. C/uLS/ra/m United States Patent 3,380,309MECHANECAL LINKAGE Dougias S. Chishoim, Midland, Mich, assignor to TheDow Chemical Company, Midland, Mich, a corporation of Delaware FiledMar. 21, 1966, Ser. No. 535,797 7 Claims. (Cl. 741) This inventionrelates to an improved mechanical linkage. It more particularly relatesto an improved mechanical linkage capable of positioning a point on apredetermined curved line or surface.

Frequently in the construction of buildings having curved surfaces it isdesirable to provide a guide or a tool which is readily positionable onor adjacent to the building structure in such a manner that the requireddesign is adhered to. In cases of circular or spherical structures thisis readily accomplished, for example, by pivoting an arm on the centerof the desired structure. However, oftentimes it is desirable togenerate structures wherein there is no ready access to the center. Forexample, in a spherical or spheroidal dome often a suitable geometriccenter is not available or in the case of a dome having an ellipticalcross sectional configuration the centers of generation may be remoteand inaccessible such as being positioned well within the earth.Oftentimes it is desired to support a construction unit such as abricklaying machine or the like at the end of a boom or arm and positionthe terminal portion of the boom in such a manner that it serves as aguide and determines the final form of the structure. Such a techniqueis particularly advantageous when buildings are constructed from stripsor portions of synthetic resinous foam which are adhered together toform the desired configuration.

It is an object of this invention to provide an improved mechanicallinkage adapted to position an arm on a desired curved surface.

A further object of this invention is to provide a mechanical linkagefor the multiplication or division of motion.

A further object of this invention is to provide an apparatus for thepositioning of an operating mechanism in a guided pattern capable ofgenerating a dome-like surface.

These benefits and other advantages in accordance with the presentinvention are achieved in an apparatus for the multiplication of linearmotion comprising a frame, the frame having a first end and a secondend, a first wheel disposed adjacent the first end, a second wheeldisposed adjacent the second end, a movable support, first and secondmovable wheels aifixed to the movable support, the movable support beingslideably positionable along the frame, a motion transmitting meansextending from a point adjacent the first end of the frame about thefirst movable wheel, from the first movable wheel to the first wheel,about the first wheel, from the first wheel to the second wheel andabout the second wheel, from the second wheel to the second movablewheel, about the second movable wheel and to a location generallyadjacent to the second end of the frame.

Further features and advantages of the present inven tion will becomemore apparent from the following specification when taken in connectionwith the drawing wherein:

FIGURE 1 is a schematic representation of the operation of apparatus inaccordance with the invention;

FIGURE 2 is a schematic representation of an alternate embodiment of theinvention;

FIGURES 3 and 4 depict a compact arrangement of apparatus employing aprinciple of the apparatus of FIG- URE 2; and

FIGURE 5 is a schematic representation of an operat- 3,38%,309 PatentedApr. 30, 1968 ing apparatus such as is depicted in FIGURES 3 and 4particularly adapted for tracing curved surfaces.

In FIGURE 1 there is schematically depicted an apparatus which isgenerally designated by the reference numeral 10. The apparatus 10comprises a frame or support 11 having a first end 12 and a second end13. A first wheel 15 is pivotally affixed to the first end 12 of theframe 11. A second wheel 16 is pivotally afifixed to the second end 13of the frame 11. A movable wheel support 17 is slideably disposed on theframe 11 and adapted to move between the first and second ends 12 and13, respectively. The support 17 carries a first movable wheel 18 and asecond movable wheel 19. By the term wheel is meant a pulley gear,sprocket gear drum or the like. A motion transmitting means 21 such as asprocket chain, cable or belt is affixed to the first end 12 of theframe 11 at location 22. Motion transmitting means 21 extends fromlocation 22, about the wheel 18, from the wheel 18 to the wheel 15,about the wheel 15 and toward the second end 13, about the wheel 16 andtoward the wheel 19, about the wheel 19 to location 24 generallyadjacent the second end 13 of the frame 11. A point P is disposed uponthe movable wheel support 17. A second point P is disposed on the motiontransmitting means 21 which extends between the wheels 15 or 16. Motionof the support 17 causes the point P to be moved a given distancewhereupon the point P will be moved twice the distance the support 17 ismoved. Thus, by moving the point P the point P is caused to move adistance twice that which the point P was moved. Similarly, if motion isapplied to the point P and it is moved a given distance, the point Pwill be moved one-half of that distance. Thus, the apparatus 10 providesmotion multiplication or division by a factor of 2.

In FIGURE 2 there is illustrated an alternate embodiment of theinvention generally designated by reference numeral 25. The apparatus 25comprises a frame 26 having first end 27 and second end 28. First,second and third wheels 29, 30 and 31 are disposed adjacent the firstend 27 and pivotally mounted thereon and adapted to retate aboutgenerally parallel axes. Third, fourth and fifth wheels 33, 34 and 35,respectively, are pivotally mounted on the second end 28 of the frame 26and are adapted to pivotally rotate about generally parallel axes. Amovable support 36 is disposed slideably adjacent the frame 26 and thendisposed intermediate the first and second ends 27 and 28. The support36 carries a plurality of wheels, the 7th, 8th, 9th and 10th wheels 37,38, 39 and 40, respectively. A motion transmitting means 41 such as abelt, cable or sprocket chain extends between the first and fourthwheels, about the fourth wheel to the ninth wheel, about the ninth wheelto the fifth wheel, about the fifth wheel to the tenth wheel, about thetenth wheel to the sixth wheel, about the sixth wheel to the thirdwheel, about the third wheel to the eighth wheel, about the eighth wheelto the second wheel, about the second wheel to the seventh wheel, aboutthe seventh wheel to the first wheel and to the fourth wheel.Advantageously, a tensioning means 43 such as a spring is disposedwithin the motion transmitting means of 41 and adapted to maintaintension thereon. A portion of the motion transmitting means 41 issecured to the frame at a location 44. A point P is disposed 0n thewheel carrier 47 and the point P is disposed on the motion transmittingmeans 41 which extends between the first and fourth wheels. Movement ofthe point P toward the second end of the frame for a distance d causesthe point P to move a distance 4d toward the first end 27 of the frame26, thus providing a constant factor of 4. Thus, in essence theapparatus 25 provides a pantographic arm with a constant ratio of 4.

In FIGURES 3 and 4 there is schematically depicted a practicalarrangement of the motion transmitting configuration of the FIGURE 2 andis generally designated by the reference numeral 5%. The apparatus 59comprises a frame 5 having a first end 52, a second end 53. A shaft isdisposed adjacent to the first end 52 and supports first, second andthird pulley wheels 57, 58 and 59, respectively. A shaft 60 is disposedadjacent to the second end 53 and supports fourth, fifth and sixthwheels 61, 62 and 63, respectively. A movable wheel support 65 isdisposed between the first and second ends 52 and 53 for frame 51. Thepulley support 65 supports a first shaft 67 which carries seventh andeighth wheels 69 and 70, respectively. A second shaft 71 carries theninth and tenth wheels 72 and 73, respectively. A motion transmittingmeans such as a belt, cable or sprocket chain 75 passes about the wheelsin the manner as demonstrated in PEG- URE 2 and operating means 76 isafiixed to the motion transmitting means 75 extending between the firstand fourth wheels and an actuating means 77 is aiiixed to the support65. A pivot 78 is affixed to the first end 52 and frame 51.

In FIGURE 5 there is a schematic representation of an apparatus 89having a motion multiplication means 50 as illustrated in FIGURES 3 and4 pivotally ailixed by its first end 52 and pivot 78 to a rotatablesupport 81. The support 81 is pivotally aiiixed to a base 82 by means ofa pivot 83 having an axis of rotation which is in a plane normal to theaxis of rotation of the pivot 78. Beneficially, a support or guide wheel84 is affixed to the support 81 and adapted to engage the base 82. Atemplate 85 is affixed to the base 81 generally adjacent to the pivot78. The base 85 has an edge 86 which defines a desired curve and isadapted to engage the actuating means 77 of the apparatus 50 and causethe operating means 76 to be positioned along the frame 51 in proportionto the displacement of the actuating means 77 caused by the edge ormodel surface 86. Thus, the apparatus by rotation of the apparatus 50about the pivot 78 and rotation of the base about the pivot 83 permitsthe operating means 76 to be positioned on a curved surf-ace ofgeneration four times the size of the surface of generation of the edge86.

Beneficially either of the embodiments of the apparatus in accordancewith the present invention are advantageously employed for suchapplications as the construction of buildings having generally circularcross sections, for the rotation of radiating devices such as thoseemitting high energy ionizing radiation about a center remote from theapparatus. Also beneficially, such radiation devices as radar antennasare rotated without the necessity of providing large circular tracks orbearings.

As is apparent from the foregoing specification, the apparatus of thepresent invention is susceptible of being embodied with variousalterations and modifications which may differ particularly from thosethat have been described in the preceding specification and description.For this reason, it is to be fully understood that all of the foregoingis intended to be merely illustrative and is not to be construed orinterpreted as being restrictive or otherwise limiting of the presentinvention, excepting as it is set forth and defined in the heretoappended claims.

What is claimed is:

1. An apparatus for the multiplication of linear motion comprising aframe, the frame having a first end, a second end, a first wheeldisposed adjacent the first end, a second wheel disposed adjacent thesecond end, a movable support, first and second movable wheels affixedto the movable support, the movable support being slideably positionablealong the frame, a motion transmitting means extending from a pointadjacent the first end of the frame about the first movable wheel, fromthe first movable wheel to the first wheel, about the first wheel, fromthe first wheel to the second wheel, about the second wheel, from thesecond wheel to the second movable wheel and to a location generallyadjacent the second end of the frame.

2. The apparatus of claim 1 wherein the motion transmitting means isresiliently secured to the frame.

3. The apparatus of claim 1 wherein a plurality of wheels are fixedrotatably to the first end and a like number of wheels are atfixed tothe second end; a number of movable wheels mounted on a slideablesupport and disposed intermediate the wheels on the first and secondends wherein the linear motion transmitting means primarilyinterconnects slideable wheels adjacent the first end and slideablewheels adjacent the second end with the wheels of the first end and thesecond end, respectively, by passing about at least a portion of theperiphery thereof and the linear motion transmitting means extendingbetween not more than two wheels of the first end and of the second end.

4. The apparatus of claim 3 including a support; a pivot pivotallysecuring the first end of the frame to the support; and means toslideably position the movable support in a predetermined pattern.

5. The apparatus of claim 4 wherein the support is pivotally supportedto rotate about an axis generally normal to the axis of the pivotsecuring the first end of the frame to the support.

6. The apparatus of claim 5 wherein the movable support has affixedthereto a follower, a template positioned adjacent the frame, thetemplate having an edge which engages the follower and thereby positionsthe movable support in a predetermined manner.

7. The apparatus of claim 1 wherein a separating means is affixed to thelinear motion transmitting means at a location wherein the linear motiontransmitting means extends between a wheel of the first end and a wheelof the second end.

No references cited.

FRED C. MATTERN, In, Primary Examiner.

C. J. HUSAR, Assistant Examiner.

1. AN APPARATUS FOR THE MULTIPLICATION OF LINEAR MOTION COMPRISING AFRAME, THE FRAME HAVING A FIRST END, A SECOND END, A FIRST WHEELDISPOSED ADJACENT THE FIRST END, A SECOND WHEEL DISPOSED ADJACENT THESECOND END, A MOVABLE SUPPORT, FIRST AND SECOND MOVABLE WHEELS AFFIXEDTO THE MOVABLE SUPPORT, THE MOVABLE SUPPORT BEING SLIDEABLY POSITIONABLEALONG THE FRAME, A MOTION TRANSMITTING MEANS EXTENDING FROM A POINTADJACENT THE FIRST END OF THE FRAME ABOUT THE FIRST MOVABLE WHEEL, FROMTHE FIRST MOVABLE WHEEL TO THE FIRST WHEEL, ABOUT THE FIRST WHEEL, FROMTHE FIRST WHEEL TO THE SECOND WHEEL, ABOUT THE SECOND WHEEL, FROM THESECOND WHEEL TO THE SECOND MOVABLE WHEEL AND TO A LOCATION GENERALLYADJACENT THE SECOND END OF THE FRAME.